Metal content of airborne particulate matter in edinburgh

• Main Author: Hibbs, Leon R
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2002
• Subjects: Environmental science

Daily 24 hour (00:00 - 24:00) co-located PM10, PM2.5, and Black Smoke samples were collected for a period of 1 year (September 1999 to September 2000) at an urban background site in central Edinburgh, and monthly at a rural site 30 km SSW of Edinburgh. Sample mass concentrations were determined gravimetrically, and the daily water and acid (2.8:1 HCl/HNO3 v/v) extractable metal concentrations of Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb, determined by ICP-MS. Median urban background PM2.5 water soluble metal concentrations ranged from 0.05 ng m-3 for Ti to 5.06 ng m-3 for Pb, and in PM10 from 0.18 ng m-3 for Ti to 11.74 ng m-3 for Fe. Median PM2.5 total (water + acid) extractable metal concentrations ranged from 0.30 ng m-3 for As to 27.60 ng m-3 for Fe, and in PM10 from 0.37 ng m-3 for As to 183.44 ng m-3 for Fe. Fe concentrations represented c. 80% of the total (water + acid) metal exposure from metals analysed in the PM10 fraction, although Pb and Zn constituted over 50% of the water soluble metal exposure in PM2.5. Significant seasonal differnces (P <0.05) were observed in the metal concentrations, which varied with metal, coupled with an overall shift towards a higher proportion of acid extractable/lower proportion of water soluble metal in the winter months. Seasonal differences were also present in the urban : rural ratio, which ranged from ~3 in the spring to up to ~10 in winter. Urban background metal concentrations were also found in general to correlate more strongly with BS ‘mass concentration equivalent’ than with PM10 or PM2.5 mass concentrations. Hierarchical clustering of 5 day air mass back trajectories demonstrated that there were significant differences (P <0.05) in metal concentrations (ng m-3) and metal ‘enrichment factors’ (EFs, ng μg-1 particulate matter) depending on air mass source/direction.